Process of detinning.



UNITED s raws "PATENT OFFIOE.

FRANZ VON KUGELGEN AND GEORGE O. SEWARD, OF HOLOOMBS ROCK,

VIRGINIA, ASSIGNORS, BY MESNE ASSLGNME COMPANY, A CORPORATION OF Nl'lW YORK.

PROCESS OF DETiNNlNG.

NTS, TO TIN PRODUCTS Specification of Letters Patent.

Patented April 30, 1907.

Appl cation tiled August 4, 1905. Renewed March 30, 1907. Serial No. 365,603

To all, whomz'l' III/1.1. concern.-

Be it known that we, FRANZ VON KUGEL- GEN, a suhject of the (iernnin. Emperor, and GEORGE O. Snwano, a citizen of the United States, both residing at llolcomhs Rock, in the county of Bedford and State of Virginia, have jointly invented certain new and useful Improvements in Processes of Detinning, of which the following is a specilicatiou.

This invention aims to economically recover the tin from tin scrap.

in our application No. 189,272, tiled January 16, 1904, we have described a process of detinning wherein the scrap is placed in a vessel and dry chlorin is admitted thereto. attackin the tin and forming stannic chlorid, which is condensed upon the walls.of the vessel. It is essential to the success of this process that the temperature he carefully controlled and maintained within narrow limits. The reaction is attended by generation of heat, so that the temperature rises rapidly. The temperature must always he kept below the point at which iron-chhn'id is formed. If, owever, to avoid this result the temperature IS kept too low, the dgtinning is slow and not so complete as it. should be. In order to secure a good practical result, it is advisable to keep the temperature as high as possible, but always below the temperature at which the iron is attacked. ln our said application we have described a means of t avoiding the ohje'ct ionahle overheating, while keeping the temperature high enough for efliciency; namely, by limiting the amount of chlorin introduced, the inllow of chlorin being varied according to the temperature, so as to keep the heat up near to, but. always below, the prohibitive point. Auxiliary to this is the external cooling of the vessel, as by the application of a water jacket, which hastens the process and gives further control of the temperature.

Our presentinvention provides another means of keepin the temperature within control; namely, y limiting the amount of tin scrap proportionally to the volume of the vessel or reaction chamber. trol the reaction, and consequently the heat of reaction, by limiting the proportion of tin, instead of by limiting the proportion of chlo- Thus we con- I rin. \Ve also apply by preference external cooling, as by a water jacket.

in practicing our invention we put a relativclysmall quantity of tin scrap intoachamher of given size, and introduce dry chlorin thereinto without limit. Even though the ot' the reactive proportion, the heatgenerated hy the reaction is dissipated through the contents of the tank, which keeps down the temperature. It is impossible to lay down any deli nite limits of proportion for the. successful n-actice' of our invention, but with a chamber of 40 cubic feet capacity, a charge of 150 pounds of tin scrap has given successful results.

The resulting stannic chlorid may be removed by the means set forth in our said application, or in various other ways.

lure so that the iron is not attacked is as follows: --lnstead of limiting the amount of chlorin or amount of scrap used in a vessel of t a given size, we use at once such a powerful current of chlorin that the same is present in great excess above the reactive propor tion. (lilorin is now passed throu h in such t alarge volume that the current of cool gas How ing thrtmgh the detinning tank exerts a cooling action on the contents.

l The heat of the reaction is carried away by the st ream ot' chlorin and the temperature is thus kept so low that the iron of the scrap is not at tacked.

We claim as our invention l. The recovery of tin from tin scrap by treating the latter in a closed vessel with dryi chlorin to form stannic chlorid, and s0 limiting the quantity of scrap that the heat gener ated by the reaction is ahosrbed by the contents of the vessel and the temperature prevented from rising to a point at which the iron is attacked.

2. The recovery of tin from tin scrap by treating the latter in a closed vessel with dry chlorin to form sta'nnic chlorid, so limitin l the uantity of scrap thatthe heat generated by the reaction is a )SUllKtl by the contents of the vessel, and water-coohng the vessel, t whereby the temperature is kept below that at which the iron is attacked.

Another way of controllin the tem era chlorin 15 present in volume much in excess I 3. The reccvez y of tin Tom 2111 sem by In Witness whereof, We have her eundzo to .reatmg theiatter 111 a, closed vessel with dry signed our names 111 the presence of two subchlorm to form stamina chlond, and passing scnbmg wztnesses.

through the vgssjafs'lich a, surplus of chiorfm -1 Y 1 I aboveine @m'ou'nt necessary for the remtisn g gg b that the Ba t genermed by the yeackien is ab,- ssrbed by the large ameunt'n'i cealgas and Wwne sses: the temperature thereby kept blow him @330. .T. LANCASTER,

poimgt which the iron is'attacked, 7 1 Farm Kmnmz. 

